Variable displacement tubing pump



March 17, 1959 l.. v. soRG ErAL 2,877,714

VARIBLE DISPLACEMENT TUBING run/1P Filed oct. so, 1957 4 sheets-shet 1March 17, '1959 L. v. soRG Er'AL v y2,877,714

' VARIABLE DISPLGEMENT TUBING P UMP Filed oct. z 0, 1957 f 4sheets-sneer 4 @aver/:757m

United States Patent VARIABLE DISPLACEMENT TUBING PUMP Leonard V. Sorg,Kansas City, and John C. Lamkin,

Independence, Mo., assignors to Standard Oil Company, Chicago, Ill., acorporation of Indiana Application October 30, 1957, Serial No. 693,316

7 Claims. (Cl. 10S-149) This invention relates to pumps and moreparticularly to peristaltic pumps adapted to transfer a plurality ofstreams.

Pumps employing flexible tubes have beenproposed heretofore and in thepreviously known forms of such pumps, a flexible tube is progressivelycompressed by a series of fingers. Variations in rates of flow areobtained by providing tubing of different size or by a variable speedmotor and gear system which changes the speed of the movement of thefingers. Such means for varying pumping rate are both expensive andinconvenient.

It is, therefore a primary object of our invention to provide aperistaltic pump which is readily adjustable and which is adaptable fora plurality of separate streams. An additional object is to provide apump which is adapted for continuous duty and wherein the output of suchpump can be adjusted without interrupting the operation of the pump. Afurther object of the invention is to provide a pump of this type whichhas a long operating life. A more specific object of the invention is toprovide a peristaltic pump wherein a plurality of streams is pumpedthrough a plurality of tubes, the flow rate through each of said tubesbeing independent of each other tube. These and other objects of theinvention will appear hereinafter as the description thereof proceeds.

Briefly, our invention comprises an apparatus -for simultaneouslypumping several streams in individual tubes with a single constant speeddrive. The variability in the pumping rate is obtained by controllingthe extent to which the tubing may expand upon the release of thefingers and by the number of fingers involvedinvthe pumping action overa given length of the tubing. The capacity of each tubing is adjusted bya controlled positioning of the contact plate associated with eachfinger, the contactplate being positioned by appropriate springs and setscrews. The number of fingers involved in the pumping action on theother hand can be determined by limiting the number of adjacent backingplates which can cooperate with the pumping fingers.

Further details of construction and advantages of our invention will bedescribed in connection with a preferred embodiment thereof illustratedin the accompanying drawings wherein:

Figure l is a top plan view;

Figures 2 and 3 are front elevations with parts removed to illustratethe drive mechanism;

Figure 4 is a side view of the apparatus in Figures l to 3;

Figure 5 is a `front View with an end plate designed to accommodate sixtubes;

Figures 6 and 7 illustrate how the pumping capacity lcan be varied bypositioning the recoil plate when using a large pumping tube; and

Figures 8 and 9 schematically illustrate the adjustment of the backingplate to control pumping rate.

For a constant speed drive the flow rate of our pump is dependent onlyupon the volume of fluid trapped within the tube 10 as the fingers11A--11L move forward f 2,877,714' Patentedv Mar. 1 7, 1959progressively. By our invention the volume of trapped liquid can bevaried within broad limits in two ways.

The pump operates by moving the series of fingers 11A-IIL against theelastic tube 10 which is held in place by the adjustable plates 12.These plates serve to locate the tube of selected size in properposition with respect to the fingers 11A-IIL. Each plate 12, 12a and 12bis supported by a pair of adjustable threaded rods 13. These rods passthrough the casing 14 of the apparatus and have one end pivoted by aball-type joint 15 to the backing plates 12, 12a and 12b allowinghorizontal and vertical tilting of each plate. The springs 16 hold theplates 12, 12a and 12b against the tubes 10.

The fingers 11A-IIL are operated from a cam 17 mounted on a shaft 18driven by pulley 30 and are pivoted on bearing shaft 19. As the camshaft 18 is rotated, the associated cams 17 cause the fingers 11A11L tooscillate about the bearing shaft 19. As the fingers 11A-IIL moveforward, i. e. toward the backing plates 12, 12a and 12b, they squeezethe rubber tube 10 against the plates 12, 12a or 12b. The forward andbackward position and the horizontal and vertical angle of each plate iscontrolled by tightening or loosening the nuts 20 on the four rods 13supporting each plate 12, 12a or 12b.

Some control can be obtained by slanting the plates 12, 12a and 12b sothat the number of figures involved in the pumping action is reduced.Figure 2 shows the positioning of the plates 12, 12a and 12b for maximumthroughput and Figure 3 shows the positioning of the plates 12, 12a and12b for a lesser throughput.

Figures 6 and 7 show how the `capacity of the pump can be varied with atube 10 which is large enough to occupy the entire space within whichthe fingers 11A--11L operate. The volume of the tube embraced by thefingers is dependent upon the extent to which the tube 10 is permittedto resume its original shape when the center fingers 11F and 11G reachthe point of most backward travel.

Figure 6 represents a positioning of the tube 10 in which the plates 12,12aI or 12b are disposed so that When any finger is at its mostwithdrawn position with respect to a backing plate 12, the tube 10 doesnot open completely.

Figure 7 represents the setting of the plates 12, 12a and 12b which isused if a maximum fiow through tube 10 is desired. Here it will be notedthat the maximum I. D. of the portion of the tube embraced by thefingers is equivalent to the normal I. D. of the tube whereas in Figure6 the I. D. at 22 is substantially less than the full capacity of thetube 10. Accordingly,` in Figure 7, the volume 23 entrapped between theouter pair of fingers 11A and 11L is the maximum obtainable.

From Figures 6 and 7 it will be apparent that by adjusting the backingplate 12, the capacity of the pump is varied and controlled. Thiscontrol is possible on each of the plurality of tubes 10 of Figures 2and 3 and the adjustment is independent of each of the individual tubes10 in the pump.

Figures 8 and 9 illustrate a system for positioning the tube 10 toobtain variable flow rates wherein the outside diameter of the tube 10is such that it does not occupy completely the space between the lingers11 and the volume entrapped in the tube 10 is dependent upon which pairof fingers will act to close the tube at two points thereby trapping theliquid therebetween. In Figure S, representing the maximum flow rate,the backing plate 12 is positioned so that the tube 10 is simultaneouslyclosed by the most remote fingers 11A and 11L in the array. On the otherhand, in Figure 9, the section is illustrated wherein something lessthan the total span of fingers closes space portions of the tubesimultaneously to entrap the uid volume 25 being pumped. In Figure 9,the backing plate 12 is slanted by adjusting the rods 13 so that fingers11A and ,11L close the tube 10. This is accomplished by allowing oneside of the plate 12 to travel with the tube 10 as the finger 11 moves.

The plate 12 is anchored on the other side by tightening thecorresponding adjusting nut 20 so that the tube 10 will close when afinger 11] has reached its forward position. The nuts adjusting thefirst side of the plate are loosened so that the spring 16 displaces theplate 12 to the position shown which allows the tube 10 to be closedbefore the end finger 11L in the array reaches its maximum forwardposition. forwardly with the tube 10 closed as shown in Figure 9.

Referring to Figure 9, the adjusting rod 13, being provided with theball-type joint 15 shown in Figures 8 and 9, allows the plate 12 to beslanted at an angle in relation to the rod 13. The plates 12, 12a and12b are drilled and ground to hold a small spherical bearing 26 which isheld in place by a washer 27 to provide a universal joint. The springs16 override the rods 13. Ball joints are provided at the corners of allbacking plates 12, 12a and 12b.

Figure shows an end plate 28 with three tubes 10 although a plurality ofsix tubes may be operated Within the pump. Erosive action of the endplate 28 upon the ow tube is prevented by providing the grommets 29 inthe end plate 28. Removal -of the end plate 28 reveals the apparatus asshown in Figures 2 and 3 havin-g the individually controllable backingplates 12, 12a and 12b. A set of four studs or rods 13 attached byuniversal joints at the backing plate 12 and the associated springs 16is the means whereby the distance between the fingers 11 and the backingplates 12, 12a and 12b may be varied. The positions of the backingplates 12, 12a and 12b are adjustable by means of nuts 20 upon thethreaded studs or rods 13. Each Iof the three backing plates 12 and 21is individually and separately variable which permits the control of theseparate fiows of the plural streams in the tubes 10.

From the above it will be apparent that we have attained the objects ofour invention by providing an apparatus in which the flow in anyparticular stream can be adjusted during operation of the pump withoutaffecting any Aof the other streams. This can be done Without modifyingthe drive mechanism and without varying the size of the tube used.

Although we have described our invention with ref ence to preferredembodiments thereof, it should be understood that these are by way ofillustration only. Accordingly, other modifications and techniques arecontemplated and can be made by those skilled in the art withoutdeparting from the spirit and scope of the invention.

What we claim is:

l. Pumping means comprising a housing having a pair of spaced walls, ashaft supported in said housing, an

The end linger 11L then completes its travel l array of pumping fingersjournalled on the said shaft to provide a common pivotal axis therefor,each of said fingers extending upwardly between said walls, a bifurcatedyoke on the lower ends of said lingers, a second shaft journalled in thesaid housing, a series of cams fixed to the said second shaft, each camengaging one of said yokes, individual tube-supporting plates mounted inthe housing between said walls, said fingers being successivelyoscillatable about the first shaft in response to rotation of said camshaft to swing said fingers towards said tubesupporting plates,resilient means adjustably supporting said plates, and a plurality offiexible tubes extending through said housing between said array offingers and said tube-supporting plates, said tube-supporting platesbeing individually adjustable to vary the pumping rate of each tubeindependently of each other tube.

2. Pumping means as defined in claim l, the spacing of said plates fromsaid array of fingers being slightly less than the internal diameter ofa tube passing through said housing.

3. A peristaltic pump comprising in combination a pump housing, an arrayof elastic tubes extending through said housing, an array oftube-compressing fingers in said housing, a first shaft to which saidfingers are journalled intermediate their ends, a second shaft, parallelto the first, a plurality of cams on said second shaft, said camsengaging cam follower means on the ends of said fingers, wherebyrotation of said cams actuates said lingers successively against saidtubes, and stop plate means backing said array of elastic tubes, saidstop plate means being individually and independently supported inopposition to the action of said ngers whereby the pumping capacity ofeach tube is independently adjustable by the position of the stop platemeans.

4. The pump of claim 3 wherein the stop plate means are adjustable fromend to end thereby to control the maximum span of fingers in said array.

5. The pump of claim 3 wherein the capacity of the pump is adjusted bythe positioning of the individual stop plate means associated with thecorresponding tube so as to limit the full expansion of the tube.

6. The pump of claim 3 wherein said elastic tubes are all of the sameinternal flow capacity.

7. The pump of claim 3 wherein said housing includes spaced end plates,said end plates being provided with a plurality of pairs of alignedtube-receiving and positioning ports, one pair for each of said elastictubes.

References Cited in the file of this patent UNITED STATES PATENTS

